Please Place Your Seat in the Full Upright Position: A Technical Framework for Landing Upright Radiation Therapy in the 21st Century

Abstract

Delivering radiotherapy to patients in an upright position can allow for increased patient comfort, reduction in normal tissue irradiation, or reduction of machine size and complexity. This paper gives an overview of the requirements for the delivery of contemporary arc and modulated radiation therapy to upright patients. We explore i) patient positioning and immobilization, ii) simulation imaging, iii) treatment planning and iv) online setup and image guidance. Treatment chairs have been designed to reproducibly position seated patients for treatment and can be augmented by several existing immobilisation systems or promising emerging technologies such as soft robotics. There are few solutions for acquiring CT images for upright patients, however, cone beam computed tomography (CBCT) scans of upright patients can be produced using the imaging capabilities of standard Linacs combined with an additional patient rotation device. While these images will require corrections to make them appropriate for treatment planning, several methods indicate the viability of this approach. Treatment planning is largely unchanged apart from translating gantry rotation to patient rotation, allowing for a fixed beam with a patient rotating relative to it. Rotation can be provided by a turntable during treatment delivery. Imaging the patient with the same machinery as used in treatment could be advantageous for online plan adaption. While the current focus is using clinical linacs in existing facilities, developments in this area could also extend to lower-cost and mobile linacs and heavy ion therapy.

Considerations for Upright Particle Therapy Patient Positioning and Associated Image Guidance

“…Recently, an option for a seated patient position was implemented in the commercially available treatment planning system RayStation (RaySearch Laboratories, Stockholm, Sweden) for proton therapy and was validated with a commercial radiotherapy chair solution offered by Q-fix (Avondale, Pennsylvania, USA) (79). Hegarty et al (17) note additional constraints concerning the patient tolerance of rotational speed and acceleration of the chair during treatment planning for photon IMRT or VMAT treatments. This is of less relevance for particle therapy, which is typically applied through few fields between which the chair rotation can be comfortably adapted.…”

“…To this end, we will summarize the clinical rationale for upright treatments and go over existing chair systems that have been constructed in the past or are currently available, focusing on those targeted for particle therapy. An overview over the requirements for an upright positioning system for photon therapy can be found in the recent review by Hegarty et al (17). We will discuss engineering considerations for upright positioning systems and options for image guidance for an upright treatment position.…”

Carbon Ions for Hypoxic Tumors: Are We Making the Most of Them?

“…At the moment, only five facilities (one in Germany, two in Japan, and two in South Korea) use C-ion gantries. A potential breakthrough in this field is the possible delivery of radiotherapy to patients in an upright position [ 119 ]; however, rotation speed, acceleration, angular range, and the tolerance of the patients to these parameters still need to be addressed [ 120 ]. In addition, both gantry and patient rotation need to combine beam raster scanning with the live rotation of the beam or the target.…”

Upright patient positioning for gantry-free breast radiotherapy: feasibility tests using a robotic chair and specialised bras

“…Selecting rotating patient positioning systems over such large gantries could clearly lead to cost savings for particle therapy ( 1 ). Even for conventional radiotherapy with photons, gantry-free radiotherapy is being proposed as a means to bring about reductions in room cost, size and shielding ( 2 , 3 ).…”

“…Further research into upright positioning for a cohort of 16 patients who received conventional, supine radiotherapy to the pelvis, reports an average patient comfort score of 4.1 out of a maximum of 5 (range 3:5) for upright positioning, compared to 3.9 (range 2:5) for supine positioning (15). It has also been hypothesised that patients with obesity, heart problems, superior vena cava obstruction, phrenic nerve injury, dyspnoea, saliva accumulation etc., are likely to find upright radiotherapy more comfortable, as such pre-existing conditions are exacerbated by lying supine (1)(2)(3).…”